The Bureau of Land Management is confident it knows why 71 wild horses died at a water hole on a classified military range last July.

It took an entire year and tens of thousands of dollars for the government to figure out the reason for the horse deaths, but some questions still remain.

Read the DRI report

A year ago, 71 wild horses were found dead around a desert water hole inside the restricted Tonopah Test Range — although water hole might be too fancy a name for the depression in the playa where horses sometimes catch a muddy sip.

10 years earlier, a few miles away on the same range, more than 60 horses were poisoned because deicing chemicals washed off a runway.

When the BLM began its investigation into the most recent horse deaths, it was well aware of the previous poisonings. BLM took samples from the horses, the soil, and the water, separate from what the military collected.

“We took soil samples of the pond and we took soil samples inside and outside of the pond and sent all that material to be tested,” said Patrick Putnam with BLM.

But it looks like no one bothered to check if something manmade poisoned the horses, until months after they died.

The study released this week states the likely cause of death for the horses was high concentrations of nitrates in the water, most likely from natural sources.

The authors of the study work for Desert Research Institute. They were hired in January to conduct the study and analyze the evidence.

The authors admit that the water samples they collected and tested in February of this year are not the same as the water the horses drank last year. If there had been man-made contaminants in the water last July, chances are those chemicals could have degraded and disappeared by the time DRI entered the picture.

The samples collected by BLM last July were never conclusive for manmade or natural chemicals. DRI says it cannot rule out manmade chemicals, but believes the source was natural.

The study cost more than $80,000 and was considered by BLM to be a big deal. So why did they wait seven months before signing a contract to get the study started?

“Well, basically we had to gather funding for the research. We work with DOE, DOD and BLM. We all combine funds in order to go out and hammer out the contract. In contracting, we have guidelines we have to follow, which take time. The immediate thing we have to take care of was to stem the death of the horses,” said Putnam.

The military stopped using the old deicing compound more than 10 years ago, so it is unlikely the same culprit was responsible this time.

But there are many places on Nevada’s military ranges that have been used as dumping grounds for bad stuff, which is one reason Senator Harry Reid asked BLM to investigate the horse deaths to the fullest.

Now, after a year of work, several delays, and $80,000 in public funding, BLM has not yet answered the original questions.

Patrick Putnam said late Tuesday that tests were conducted on the original samples collected looking for manmade substances, but those tests were inconclusive.

One other question has yet to be answered — why did the poisoned water kill only horses? Other animals in the same area did not die. The research institute said it was unaware that horses were the only victims.

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